<!DOCTYPE html>
<html>

<head>
    <title>CSS Transition Example</title>
    <style>
        .box {
            width: 100px;
            height: 100px;
            background-color: red;
            transition-property: all;
            transition-duration: 1s;
            transition-timing-function: ease-in-out;
        }

        .box:hover {
            height: 400px;
        }
    </style>
</head>

<body>
    <div class="box"></div>
</body>

</html>